Human B cell maturation antigen, also known as BCMA; TR17_HUMAN, TNFRSF17 (UniProt Q02223), is a member of the tumor necrosis receptor superfamily that is preferentially expressed in differentiated plasma cells (Laabi et al. 1992; Madry et al. 1998). BCMA is a non-glycosylated type III transmembrane protein, which is involved in B cell maturation, growth and survival. BCMA is a receptor for two ligands of the TNF superfamily: APRIL (a proliferation-inducing ligand), the high-affinity ligand to BCMA and the B cell activation factor BAFF, the low-affinity ligand to BCMA (THANK, BlyS, B lymphocyte stimulator, TALL-1 and zTNF4). APRIL and BAFF show structural similarity and overlapping yet distinct receptor binding specificity. The negative regulator TACI also binds to both BAFF and APRIL. The coordinate binding of APRIL and BAFF to BCMA and/or TACI activates transcription factor NF-κB and increases the expression of pro-survival Bcl-2 family members (e.g. Bch 2, Bcl-xL, Bcl-w, Mc1-1, A1) and the downregulation of pro-apoptotic factors (e.g. Bid, Bad, Bik, Bim, etc.), thus inhibiting apoptosis and promoting survival. This combined action promotes B cell differentiation, proliferation, survival and antibody production (as reviewed in Rickert R C et al, Immunol Rev (2011) 244 (1): 115-133).
Antibodies against BCMA are described e.g. in Gras M-P. et al. Int Immunol. 7 (1995) 1093-1106, WO200124811, WO200124812, WO2010104949 and WO2012163805. Antibodies against BCMA and their use for the treatment of lymphomas and multiple myeloma are mentioned e.g. in WO2002066516 and WO2010104949. WO2013154760 and WO2015052538 relate to chimeric antigen receptors (CAR) comprising a BCMA recognition moiety and a T-cell activation moiety. Ryan, M C et al., Mol. Cancer Ther. 6 (2007) 3009-3018 relate to anti BCMA antibodies with ligand blocking activity that could promote cytotoxicity of multiple myeloma (MM) cell lines as naked antibodies or as antibody-drug conjugates. Ryan showed that SG1, an inhibitory BCMA antibody, blocks APRIL-dependent activation of nuclear factor-KB in a dose-dependent manner in vitro. Ryan also mentioned antibody SG2 which inhibited APRIL binding to BCMA not significantly.
A wide variety of recombinant bispecific antibody formats have been developed in the recent past, e.g. by fusion of, e.g. an IgG antibody format and single chain domains (see e.g. Kontermann R E, mAbs 4:2, (2012) 1-16). Bispecific antibodies wherein the variable domains VL and VH or the constant domains CL and CH1 are replaced by each other are described in WO2009080251 and WO2009080252.
An approach to circumvent the problem of mispaired byproducts, which is known as ‘knobs-into-holes’, aims at forcing the pairing of two different antibody heavy chains by introducing mutations into the CH3 domains to modify the contact interface. On one chain bulky amino acids were replaced by amino acids with short side chains to create a ‘hole’. Conversely, amino acids with large side chains were introduced into the other CH3 domain, to create a ‘knob’. By coexpressing these two heavy chains (and two identical light chains, which have to be appropriate for both heavy chains), high yields of heterodimer formation (‘knob-hole’) versus homodimer formation (‘hole-hole’ or ‘knob-knob’) was observed (Ridgway J B, Presta L G, Carter P. Protein Eng. 9, 617-621 (1996); and WO1996027011). The percentage of heterodimer could be further increased by remodeling the interaction surfaces of the two CH3 domains using a phage display approach and the introduction of a disulfide bridge to stabilize the heterodimers (Merchant A. M, et al, Nature Biotech 16 (1998) 677-681; Atwell S, Ridgway J B, Wells J A, Carter P., J Mol. Biol 270 (1997) 26-35). New approaches for the knobs-into-holes technology are described in e.g. in EP 1870459A1. Although this format appears very attractive, no data describing progression towards the clinic are currently available. One important constraint of this strategy is that the light chains of the two parent antibodies have to be identical to prevent mispairing and formation of inactive molecules. Thus this technique is not appropriate for easily developing recombinant, bispecific antibodies against two targets starting from two antibodies against the first and the second target, as either the heavy chains of these antibodies and/or the identical light chains have to be optimized. Xie, Z., et al, J Immunol. Methods 286 (2005) 95-101 refers to a format of bispecific antibody using scFvs in combination with knobs-into-holes technology for the FC part.
The TCR/CD3 complex of T-lymphocytes consists of either a TCR alpha (α)/beta (β) or TCR gamma (γ)/delta (δ) heterodimer coexpressed at the cell surface with the invariant subunits of CD3 labeled gamma (γ), delta (δ), epsilon (E), zeta (0, and eta (q). Human CD3ε is described under UniProt P07766 (CD3E_HUMAN).
An anti CD3ε antibody described in the state of the art is SP34 (Yang S J, The Journal of Immunology (1986) 137; 1097-1100). SP34 reacts with both primate and human CD3. SP34 is available from Pharmingen. A further anti CD3 antibody described in the state of the art is UCHT-1 (see WO2000041474). A further anti CD3 antibody described in the state of the art is BC-3 (Fred Hutchinson Cancer Research Institute; used in Phase I/II trials of GvHD, Anasetti et al., Transplantation 54: 844 (1992)). SP34 differs from UCHT-1 and BC-3 in that SP-34 recognizes an epitope present on solely the ε chain of CD3 (see Salmeron et al., (1991) J. Immunol. 147: 3047) whereas UCHT-1 and BC-3 recognize an epitope contributed by both the ε and γ chains. Further anti-CD3 antibodies are described in WO2008119565, WO2008119566, WO2008119567, WO2010037836, WO2010037837, WO2010037838, and U.S. Pat. No. 8,236,308 (WO2007042261). CDRs, VH and VL sequences of a further anti-CD3 antibody are shown in SEQ ID NO:7 and 8.
Bispecific antibodies against CD3 and BCMA are mentioned in WO2007117600, WO2009132058, WO2012066058, and WO2012143498. CAR compounds of antibodies against BCMA are mentioned in WO2013154760, WO2013154760, and WO2014140248.
Cell-mediated effector functions of monoclonal antibodies (like antibody dependent cellular cytotoxicity (ADCC)) can be enhanced by engineering their oligosaccharide composition at Asn297 as described in Umafla, P., et al., Nature Biotechnol. 17 (1999) 176-180; and U.S. Pat. No. 6,602,684. WO1999054342, WO2004065540, WO2007031875, and WO2007039818, Hristodorov D, Fischer R, Linden L., Mol Biotechnol. 2012 Oct. 25. (Epub) also relate to the glycosylation engineering of antibodies to enhance Fc-mediated cellular cytotoxicity.
Also several amino acid residues in the hinge region and the CH2 domain influence cell-mediated effector functions of monoclonal antibodies (Eur. J. Immunol., 23, 1098 (1993), Immunology, 86, 319 (1995), Chemical Immunology, 65, 88 (1997)] Chemical Immunology, 65, 88 (1997)]. Therefore modification of such amino acids can enhance cell-mediated effector functions. Such antibody modifications to increase cell-mediated effector functions are mentioned in EP1931709, WO200042072 and comprise in the Fc part substitutions at amino acid position(s) 234, 235, 236, 239, 267, 268, 293, 295, 324, 327, 328, 330, and 332. Further antibody modifications to increase cell-mediated effector functions are mentioned in EP1697415 and comprise amino acid replacement of EU amino acid positions 277, 289, 306, 344, or 378 with a charged amino acid, a polar amino acid, or a nonpolar amino acid.
Antibody formats and formats of bispecific and multispecific antibodies are also pepbodies (WO200244215), Novel Antigen Receptor (“NAR”) (WO2003014161), diabody-diabody dimers “TandAbs” (WO2003048209), polyalkylene oxide-modified scFv (U.S. Pat. No. 7,150,872), humanized rabbit antibodies (WO2005016950), synthetic immunoglobulin domains (WO2006072620), covalent diabodies (WO2006113665), flexibodies (WO2003025018), domain antibodies, dAb (WO2004058822), vaccibody (WO2004076489), antibodies with new world primate framework (WO2007019620), antibody-drug conjugate with cleavable linkers (WO2009117531), IgG4 antibodies with hinge region removed (WO2010063785), bispecific antibodies with IgG4 like CH3 domains (WO2008119353), camelid Antibodies (U.S. Pat. No. 6,838,254), nanobodies (U.S. Pat. No. 7,655,759), CAT diabodies (U.S. Pat. No. 5,837,242), bispecific (scFv)2 directed against target antigen and CD3 (U.S. Pat. No. 7,235,641), sIgA plAntibodies (U.S. Pat. No. 6,303,341), minibodies (U.S. Pat. No. 5,837,821), IgNAR (US2009148438), antibodies with modified hinge and Fc regions (US2008227958, US20080181890), trifunctional antibodies (U.S. Pat. No. 5,273,743), triomabs (U.S. Pat. No. 6,551,592), troybodies (U.S. Pat. No. 6,294,654).
WO2014122143 disclose anti-human BCMA antibodies characterized in that the binding of said antibody is not reduced by 100 ng/ml APRIL for more than 20% measured in an ELISA assay as OD at 405 nm compared to the binding of said antibody to human BCMA without APRIL, said antibody does not alter APRIL-dependent NF-κB activation for more than 20%, as compared to APRIL alone, and said antibody does not alter NF-κB activation without APRIL for more than 20%, as compared without said antibody. WO2014122144 discloses bispecific antibodies specifically binding to the two targets human CD3ε and human BCMA, comprising anti-human BCMA antibodies of WO2014122143. An anti-human BCMA antibody with unique properties, especially in regard to its therapeutic use as a bispecific T cell binder, is antibody 83A10, characterized by comprising as CDR regions CDR1H of SEQ ID NO:15, CDR2H of SEQ ID NO 16, CDR3H of SEQ ID NO:17, CDR1L of SEQ ID NO:18, CDR3L of SEQ ID NO:19, and CDR3L of SEQ ID NO:20, disclosed also in WO2014122143 and WO2014122144.